In process automation technology, field devices are often applied, which serve for registering and/or influencing process variables. Serving for registering process variables are sensors, such as, for example, fill level measuring devices, flow measuring devices, pressure- and temperature measuring devices, pH-redox potential measuring devices, conductivity measuring devices, etc., which register the respective process variables, fill level, flow, pressure, temperature, pH-value, and conductivity. Serving for influencing process variables are actuators, such as, for example, valves or pumps, via which the flow of a liquid in a section of pipeline, respectively the fill level in a container, can be changed. Referred to as field devices are, in principle, all devices, which are applied near to the process and which deliver or process information relevant to the process. Besides the above mentioned sensors and actuators, referred to as field devices are generally also units, which are connected directly to a fieldbus and which serve for communication with the superordinated units, such as e.g. remote I/Os, gateways, linking devices and wireless adapters. A large number of such field devices are produced and sold by the Endress+Hauser group of companies.
Such field devices are, in the case of larger plants, especially in the case of production plants, most often, arranged distributed over a very wide area. In the case of a disturbance or also for routine maintenance, these field devices must be identified and located in as short a time as possible, in order to be able to remove the disturbance on-site, respectively to perform the maintenance. In such case, the exact locating of the field device represents, most often, a problem that must be solved efficiently.
Known from DE 10163564A1 is the equipping of such a field device with a GPS module, in order to provide locational information to enable locating the field device with sufficient accuracy.
The equipping of a field device with a GPS module can, as a rule, only be performed by the field device manufacturer. Typically, the GPS module is integrated during production of the field device at the plant of the field device manufacturer. Then, the field device with the integrated GPS module is placed in operation at the plant of the field device user.
The equipping of a field device with a GPS module has the disadvantage that it is not only technically complicated, but also means additional costs.
A further disadvantage is that field devices already integrated into an automated plant and being used are only extremely difficultly retrofittable. Even in this case, the subsequent integration of a GPS module would be performed by the field device manufacturer. In this connection, the field device would be removed from the location of installation in the plant. This means, however, for the field device user, that, for the time needed for the retrofitting, a replacement field device instead of the actual field device would be integrated in the plant. This, in turn, means increased effort.